Reading the output of some modern historians, especially those working in TV, one could be forgiven for thinking that Britain is simply part of mainland Europe. There is too little understanding of the vital role the sea has played in this country's history and in the shaping of our identity and culture. As for the navy's contribution to the defence of freedom or the protection and nurturing of our trade and, thus, our economy - that is a subject best left to enthusiasts and not worth the attention of mainstream scholars.

But a change is under way. Recently, there has been an surge of scholarly interest in maritime and naval history. A number of universities - London (King's College), Aberdeen, Exeter, Hull, Greenwich and Portsmouth - now offer courses in maritime studies. The acknowledged leader of this quiet academic revolution is Nicholas Rodger, professor of naval history at Exeter University.

Nearly 20 years ago, he wrote The Wooden World, a rare book that merits the adjective 'seminal'. In it, he reversed more than a century of misconceptions about the social history of the 18th-century navy. The ludicrously brutal image of 'rum, sodomy and the lash' was replaced with a carefully drawn picture of a complex and finely balanced structure that reflected the civilian society it served. Rodger made such a convincing case that it is difficult now to understand why we ever believed all the old baloney in the first place.

Rodger's ability to take a subject we all thought we knew and to turn our perceptions on their head with common sense and painstaking scholarship is now being applied to the whole of naval history. The Command of the Ocean is the second in a groundbreaking series Penguin is publishing in association with the National Maritime Museum. The first volume, The Safeguard of the Sea, took the story from 660 to 1649; the present one continues the narrative to 1815.

This is a magnificent book, broad and ambitious in its scope, embracing not only naval affairs but also economics, geography, politics, religion and agriculture, with the ease and fluency of a polymath. The detail is meticulous. We learn, for example, that after the French defeat in the Seven Years' War, the finances of its navy were so reduced that it was no longer possible to find funds to feed the dockyard cats.

Rodger's aim is to show how Britain's naval history is enmeshed at every level, and in every area, with our national history and so he spends as much time on administrative and social matters as on operations. An exposition on the geography of Brest, for example, and the navigational hazards of the area, points up the extraordinary achievement of the British fleets in maintaining their constant patrols in such dangerous waters. A digression into 18th-century mathematics helps to explain the differences between British and French ship design.

A summary of the structure of mid-18th-century British governments shows how politics and strategy were so closely linked that the fates of admirals, and of whole campaigns, could hang on the result of a vote in the House of Commons.

Throughout the book, cherished myths are challenged and key personalities reassessed. So, Admiral Byng goes to his death before the firing squad because of the ineptness of his defenders, rather than as the result of any political conspiracy. Samuel Pepys, superb administrator though he was, hastened his own fall from office by his supercilious inflexibility towards his colleagues.

With a light touch and dry wit, Rodger keeps the story moving and the pages turning. When, in 1688, Admiral Arthur Herbert decided to oppose King James II's policy of religious toleration on the grounds of conscience, Rodger remarked that this caused some surprise among his followers who had not been aware that he had one.

The main text is supported by an impressive array of appendices, glossaries and a note of 'conventions', including exchange rates, weights and measures and comparative ranks. There is also an first-class bibliography that highlights the extent to which this book is based on new research; more than two-thirds of the entries date from post-1970.

Well-drawn plans cover all the geographical areas featured in the text and include useful additional information such as prevailing winds and currents, so essential to an understanding of naval warfare in the age of sail. Moreover, Rodger, who is Anderson Senior Research Fellow at the National Maritime Museum, has been allowed access to the museum's unrivalled collection of prints and paintings and, as a result, the 56 illustrations are excellent - and often unfamiliar.

2005 is the 200th anniversary of Trafalgar, and Nelson's death, and plans are already in place for a major national programme of events. But 2005 is also an opportunity to remind all Britons and, especially, our academics and politicians, that this country's relationship with the sea is far richer and more complex than the story of a single man and single victory, however great. The Command of the Sea - scholarly, witty, insightful and enthralling - provides the perfect textbook for such an exercise.